2. Generalised Stratigraphic Succession Map of Singhbhum
3. Singhbhum Composition
4. Succession of Singhbhum
a) Older Metamorphic Group
b) Iron Ore Group
c) Singhbhum Granite
d) Singhbhum Group
e) Dhanjori Group
f) Gangpur Group
5. Evolution Of Singhbhum Craton Lithology In The Archean
3. Singhbhum Craton lies in between
Satpura Mobile Belt in the east, north and
north-west; Eastern Ghat Mobile Belt in the
Singhbhum Craton is separated from
Bastar Craton by Mahanadi Graben.
Located in northern parts of Odisha and
The Singhbhum region of the southern
Bihar and its contiguous regions of
Mayurbhanj, Keonjhar and Bonai of
Sundergargh districts of Odisha are well known
for their rich deposits of iron and copper.
The region is traversed by Singhbhum Shear
Zone. The shear zone separates a northern
terrain of more highly metamorphosed rocks
and a southern terrain of relatively less
Age: Archean to Paleoproterozoic
5. Singhbhum Composition:
The rock succession of the tract in the south of the Shear Zone consist of a lower
Archean basement of Older Metamorphic Group abundant of Biotite tonalite gneiss.
The Iron Ore Group rocks were deposited
over the lower Archean basement.
These rocks were folded about NNE to
NNW trending fold axes and low grade
metamorphism culminating in the
emplacement of the Singhbhum Granite.
After a long period of erosion, rocks of
Singhbhum and Gangpur Groups were
laid down along the northern edge of
the stabilised ‘’Iron Ore Craton”.
The rocks of the Singhbhum Group
underwent a first generation of folding,
uplift leading to retreat of ocean and
subaerial erosion. A subsequent phase
of regional tension lead to eruption of
theolitic Dalma and Dhanjori Lavas concurrent
with the deposition of terrigenous sediments.
A second phase of folding preceded by the
emplacement of granite rocks led to the
development of Singhbhum Shear Zone that served as the favourable channel for the
7. Older Metamorphic Group:
The oldest rock lying in the south of Singhbhum Shear Zone were named by Dunn(1929)
as the “Oldest Metamorphics”.
The rock consist of predominantly hornblende schists with quartzites and quartz mica-
schists. Thee rocks are known to occur as isolated exposures within the general mass of
The “Older Metamorphics” are
intruded and partly granitised
by a suite of biotite
The closing date of metamorphism
and emplacement of the tonalite
gneiss as indicated by Rb-Sr and K-Ar
mineral and whole rock dating is 3200
8. Iron Ore Group:
The rock exposed in the southern
Singhbhum and Kenojhar and lying
unconformably over “Older
Metamorphics” was named as “Iron Ore
Series” by H.C. Jones (1934).
The Stratigraphic succession of the Iron
Ore Group begins with a locally
developed basal sandstone and
The basal beds are successively overlain
by Lower Lava, Lower Phyllite, Banded
Iron Ore, Upper Phyllite and Upper Lava
The Banded Iron Ore Formations crops
in ridges arranged in sharply bent horse-
shoe patterns. The formation has
preserved primary depositional features
such as current bedding ripple marks
scour-and-fill structures etc.
The Banded Iron Ore Formation has
provided some of the richest iron-
deposits of India.
9. Singhbhum Granite
(Type B, phase III):
The Singhbhum granite is a great batholithic
mass occupying an elongated tract of about
10,000 square km in Singhbhum, Kenojhar and
The batholith consist of several domed up
intrusions varying in composition from biotite
granodiorite to adamellite, biotite
trondhjemite and leuco-granite.
At margins of the batholith, chloritic or
epidotic granodiorite and pyroxene diorite
The main mass shows a distinct N-S or NNE-
SSW foliation in parallelism with the foliation
of the host rocks of the Iron-Ore Group.
Roof pendents of rocks of Iron Ore Group and
patches of granitised amphibolites of the older
Metamorphic Group are known within the
10. Singhbhum Group:
The rock succession lying to the north of the Singhbhum Shear Zone extends in a
series of east-west folds for 200km.
This succession has been divided into a lower Chaibasa Formation and an upper
The Chaibasa Formation nearest outcrops are exposed some 20km north.
The formation consist of high grade mica-schists, hornblende-schists and quartz
granulites. The rock were considered as more metamorphosed equivalents of
rocks exposed at Chaibasa which was later group into a much younger Kolhan
Group of Middle to Late Proterozoic age.
The term “Chaibasa Formation” has been retained in Indian Geology for its
usage for a very long time and for want of any other proper stratigraphical name
for the formation.
The Dalbhum formation consists of phyllites and banded quarzites which show a
lower grade metamorphism than the underlying rocks of the Chaibasa
Some of phyllites are considered to represent tuffs and volcanic flows.
The phyllites contain ferruginous beds and sometimes manganese mineral also.
11. Dhanjori Group:
• The group consists of a basal conglomerate, arkose, quarzite and extensive
• The succession was unconformably deposited over the Singhbhum Granite
and the rocks of Iron Ore Group.
• Equivalent volcanic rocks exposed in the Dalma hills in the north of the
Singhbhum Shear Zone are known as “Dalma Lava”.
• Southern extensions of the volcanic flows are observed in Simlipal of
Kenojhar district and Bonai of Sundergarh district in Odisha.
• Basal sediments of the Dhanjhori Group are regarded as non-marine facies
of piedmont or alluvial fan types.
• The Dalma Lava probably once covering an area of over 2000 square km.
12. Gangpur Group:
Archean rocks of the Sundergarh district in Odisha were grouped into a “Gangpur
Series”. These rocks were regarded to be older than the rocks of the Iron Ore Group.
The Gangpur rocks were shown to occupy the core of anticlinorium.
The Gangpur Group has been divided into five formation; On the basis of their
lithological similarities, the succession has been corelated with the Chilpi Ghat Group
exposed at about 120km to the west of Gangpur area.
13. Evolution of Singhbhum Craton lithology in the Archean:
got deposited in
the basin were
Partial melting of
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contributed to the
growth of OMTG
Continuation of granitic
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GRANITE TYPE A, PHASE I & II)
The Singhbhum Craton provides a well preserved and extensive Archean geological
Its tectonic evolution commonly observed in other Archean Cratons.
This includes an early phase of mafic/ultramafic submarine volcanism and Tonalite–
trondhjemite–granodiorite (TTG) plutonism to form protocratonic crust, a phase
of craton stabilization as a result of deep-crustal.